Here is what we did:
We created two entree options, hot dog or pb&j both with watermelon slices on the side.
The kids decorated their own "to go" bags with stickers. While they decorated their bags I cut rectangles of green construction paper for money. I made 1's, 5's, & 10's. I gave the kids (all but the 2 yr. old, he was more interested in playing with cars) their money and they hopped on their bikes and "drove" around to the front porch to make their orders. While I got their orders ready they rode their bikes around. Once I was outside with their lunches,